(a) Field of the Invention
Broadly speaking, this invention relates to electronic intruder-detection systems. More particularly, in a preferred embodiment, this invention relates to an electronic intruder-detection system which employs a transmission line positioned about the perimeter of the area to be protected as the sensing element.
(b) Discussion of the Prior Art
More present-day intrusion-detection systems, including those that use line sensors, such as the balanced pressure system, should be classified as "point" sensor systems, i.e., systems which are independently powered and operating detectors having a limited range (in the order of several hundred feet) and zero range resolution. Typically, when surveillance over an extended boundary is required, many such sensors are employed side by side, each covering its respective segment and reporting alarm information to a central location. By the association of an alarm with the corresponding sensor the intruder is located, resolution being given by the spacing of the individual sensors.